Yarn feeding and tensioning device and process



Dec. 16, 1952 R. M. HOFFMAN ETAL 2,621,391

YARN FEEDING AND TENSIONING DEVICE AND PROCESS Filed Oct. 20, 19492SH'EETS-SHEE4T' 1 INVENTORS ROBERT MICHAEL HOFFMAN a FRANK KERRSIGNAIGO MITTORNEY 1952 RM. HbFFMAN ETAL 2,621,391

YARN FEEDING AND TENSIONING DEVICE AND PROCESS Filed 001. 29, 1949 2sl'iEETs SHEET 2 INVENTORS ROBERT MICHAEL HOFFMAN a FRANK KERR SIGNAIGOA T'TORNE Y Patented Dec. 16, 1952 UNITE STATES YARN FEEDENG ANDTENSIONING DEVICE AND PROCESS Robert Michael Hoffman, Snyder, N. Y., andFrank Kerr Signaigo, Wilmington, DeL, assignors to E. I. du Pont oleNemours & Company, Wilmington, Del, a corporation of DelawareApplication Gctober 20, 1949, Serial No. 122,422

3 Claims. 1

This invention relates to textile staple and winding processes. Moreparticularly it relates to a device and process for feeding andtensioning yarn and delivering the yarn at very high speeds to asuitable collecting surface or intermittently to a cutting blade for theconversion of continuous filaments into staple fiber.

In the manufacture of filaments, yarns, threads and the like, it ishighly desirable to wind or deliver freshly formed filaments at veryhigh speeds. This is especially true in connection with the extrusion ofsome of the synthetic filament formers which are melt-spun and which arecapable of being drawn away at speeds heretofore thought to be entirelyimpracticable. For example, speeds in the range of from 3,000 to 6,000yards per minute and upward have been found entirely practical from thestandpoint of extrusion but difiiculties have arisen in delivering orwinding up filaments or yarns at such high speeds.

It is, therefore, an object of this invention to provide a filament oryarn take-up device capable of drawing the filamentary or funicularstructure away and maintaining it under tension until it is wound up orcut into staple lengths. A further object of the invention is to providea tensioning draw off device capable of handling yarns, ribbons, tubes,rods, artificial horsehairs, straws or other monofils or otherfilamentary structures at extremely high rates of delivery, such as from3,000 to 6,000 or even 10,000 yards per minute. Other objects will beapparent from the description that follows.

The objects of this invention are accomplished by the use of anapparatus which consists of a chamber equipped with a plate having aring of blower holes. Preferably, there are two such chambers, circularin shape and mounted so that the plates are directly over each otherwith a small space separating them and with the holed surface of eachlying face to face. Actually, only one plate need be perforated, but, inpractice, both plates are preferably blower plates. Each of the holescomposing the ring of the upper plate is machined so that emitted air isdirected down and approximately tangentially forward with respect to thering of holes. In the lower plate the holes direct the air up andapproximately tangentially forward. A suction inlet is located in thecenter of one of the chambers, preferably in the top center of the upperchamber. The suction inlet facilitates the stringing up operation, butit is not necessary for advancing the yarn after that operation iscompleted. Upon passing through the yarn inlet and through the spacebetween the two blower plates, the advancing yarn is given a rotarymotion by the tangential jets of air. These jets do not rotate; the yarnis merely propelled from one jet to the next so that it moves at a highspeed in a circular path.

It thereby acquires a centrifugal motion and tends to move radiallyoutward. One or more times each revolution the protruding end passes aproperly positioned knife blade which cuts the fiber into short lengths.

The apparatus, then, comprises means for feeding a fiuid under pressureto an area of turbulence and means for feeding the traveling structureto this area. By releasing the fluid under pressure from the plenumchamber into a small space the fluid moves at a high speed. By feedingthe structure into this area of rotating, high speed turbulence, thestructure is rotated at high speeds.

Reference is made to the discussion below and to the figures which aregivenonly for illustration and of which:

Figure l is a plan view partly in section;

Figure 2 is a side elevation partly in section taken on line 22. ofFigure 1;

Figure 3 is a plan view of a backup plate, taken on 33 of Figure 4;

Figure 4 is a side view of the backup plate attached to a slotted plate;

Figure 5 is a bottom plan View, taken on 55 of Figure 4, of a slottedplate;

Figure 6 is a plan view of a spiral slotted plate; and

Figure 7 is a detail of a jet hole in the plate of Figure 6.

In Figure 2, a yarn inlet l is centrally located perpendicular to upperblower disk 2. The inlet is in the top of tubular member 3, which alsohas yarn outlet l at the bottom. Situated close to upper blower disk 2is lower disk 5. In each of these disks is a plurality of blower holesor slots ii. While one blower hole is suflicient, for greater uniformityof fluid distribution and hence, yarn movement, a plurality ispreferred. For example, each plate may be equipped with a ring of 36blower holes uniformly spaced, each hole having a cross-sectional areaof 0.0016 square inch. The holes are conveniently formed by machiningrectangular slots in the peripheral edge of the blower plate but may beformed in any desired manner and with any cross-sectional shape. Thplates are mounted directly over each other with a small space (aboutinch) separating them and with the discharge end of each ring of holeslying face to face. Each of the holes composing the ring of the upperplate is formed so that emitted air is directed down and approximatelytangentially forward with respect to the ring of holes. In the lowerplate the holes direct the air up and approximately tangentiallyforward. The holes are formed at an angle of from 10 to 30 from thehorizontal. Actually, the tilt of the hole from the horizontal may begreater than 30 but at the greater angles eiiiciency drops. Accordingly,the holes are usually drilled at angles of from 10 to 3 50 from thehorizontal with angles of to 30 being preferred.

Situated around the upper disk is a housing 7 bearing flange 8 and fluidinlet 9. Similarly, other lower disk has a housing If], flange H andinlet [2. The housings are suitably attached to the respective disks bymeans, for example, of screws I3 and spacers M. An upper pressurechamber [5 and a lower chamber of a desired size are thereby formed. Theupper section comprising the blower plate, housing and yarn inlet may bemounted in any convenient way (not shown) independent of the mounting ofthe lower section, or the two sections may be bracketed togetherproviding for suflicient clearance for the rotating yarn and the unitmay be suitably mounted on a frame (not shown).

In operation the yarn I! or article to be handled is fed into the yarninlet l. The device may be inverted and the yarn fed upwards to it ifdesired. Usually, the device is used in the position shown. Air or thefluid being used is fed under pressure into the upper plenum chamber 15via inlet 9 and into plenum chamber I6 via lower inlet i2. Since the airjets in the plates, consisting of holes and/or radial slots, are tiltedat an angle of 30 or less to the horizontal, the air from both plates isled into the space between the plates in a rotating or whirling manner.As a result of this rotation, air is exhausted from the central portionof the area between the plates and a suction is created in the tubularmember 3 or in the yarn inlet I. When a yarn is introduced in the inlettube, it is pulled down between the plates and then outwardly. Anauxiliary jet l8 may be located on the tubular member 3. Forcing fluidthrough this inlet creates additional suction and facilitates thestring-up. After the yarn reaches the space between the plates,designated as the area of turbulence or yarn rotation I9, it is pickedup by the air from jets 8, blowing at right angles to the radial exhaustof air and is propelled in a rotary motion from jet to jet. Thisrotational motion gives rise to a centrifugal force, some of whichappears as tension in the yarn. The yarn is led to a suitable wind-updevice or to a knife edge placed at a desired distance from the flangeedge 8 or I i to cut staple of proper length. Generally a plurality ofknife edges are placed about the periphery of the blower plates.

The plates 2 and 5 are separated by a short distance of inch to 1% inchor up to A; inch. The distance will, of course, depend upon such factorsas the size of the article passing through the device, the pressureused, etc. It is advantageous to construct the device of this inventionso that the area of rotation l9 may be varied during operation.Adjustable plates permit ready control of R. P. M. of the yarn and theuse of initial large spacings to facilitate string-up.

Normally, the pressure that is employed is from to 180 lbs/sq. in. Anysuitable fluid may be used. Air, of course, is preferred in view of itsavailability, and is used under a pressure of lbs. per square inchgauge. Steam is also very useful because of its low cost, and throughits use a yarn may be heat set on the run. Other fluids which may beused include nitrogen, hydrogen, argon, helium, water, alcohols, oils,liquid compositions for lubricating, softening or sizing the filaments,or other similar materials.

The plates may vary in diameter from 2 to 8 inches. They may be of anydesirable thickness provided, of course, that they withstand thepressure and that the passageways do not impede fluid flow. Generally,the plates are flat but they need not be. Plates of concave contour maybe employed, but for convenience in construction, flat plates arepreferred.

As shown in Figure 5 the circular holes shown in Figure 1 may bereplaced by narrow slots 20 cut at even a lower angle. The holes areusually cut at a 15 angle. The slots in plate 2i, as shown in Figures 4and 5, may be cut at an angle of 10 to the horizontal, being about 1"deep as measured along the radius, 3% in. wide and contained in a 4 inchdiameter plate. With the slots almost as long as the radius, almost theentire rotating yarn segment is acted upon rather than just the tip asis the case with the hole jets. Used with slotted plate 2| is a backupor support plate 22 shown in Figure 3. This plate is bolted to plate 2!as shown in Figure 4. The plate 22 has portions 23 cut away, which arealigned with the slots 20 when the two plates are bolted together.

Another modification is shown in Figure 6. This is a spiral cutter 24 inwhich the diameters of the plate increases as the length of the rotatingyarn grows. The R. P. M. depends on the length of protruding yarn anddecreases as the length protruding increases. With the jets 25 arrangedas shown in the two oil-set circles, giving a spiral effect, theretardation of the protruding yarn segment by the relatively slow movingair outside the cutter plate periphery is avoided. Shown in Figure 7 isa detail of a jet 25. These jets can be replaced with advantage byslots. Fewer drillings are necessary. About four slots are all that areneeded. Further, the slotted spiral cutter is more eflicient.

The rate of yarn delivery and/or tension on the yarn can be variedwidely by changing the number, size and location of the fluid jets or bychanging the fluid pressure or character or composition of the fluid. Byarranging the jets in a larger or smaller diameter circle, thecentrifugal force created can be substantially increased or diminished.The number of jets can be greatly increased or decreased in the samediameter circle and made smaller or larger in cross-sectional area as isdesired. The angle at which the slots or other equivalent jet openingsare formed around the periphery of the blower disc also may be variedwidely.

The rate of yarn delivery may also be increased by the use of auxiliarydevices. For example, the yarn may be passed through an auxiliary airjet prior to entering the turbo-cutter. The jet is controlled toaccelerate the yarn yet avoid looping. In another arrangement a longtube of small diameter, for example of 4 inch length and inch insidediameter, is vertically attached to the yarn inlet I and the yarn is fedinto it prior to passing to the cutter. The use of this results inincreased through-puts without increased air consumption.

From the above it can be seen that under the same conditions ofoperation, more yards/min. of filament are processed with the inlet tubeattachment. The auxiliary aspirator draws the yarn away from thespinneret and feeds it to the cutter under low tension. The inlet tubepermits the air pumping action of the device to act for a longer time onthe yarn. Some care has to be exercised to prevent jamming the cutter byfeeding it too much yarn, but usually no difiiculty is encountered.

By the use of this invention yarns or similar articles may be tensioned,fed to desired windup or package forming devices, or cut into staplelength at high speeds. For example, delivery rates may be from 3,000 to10,000 yards/minute. There are no moving mechanical parts that wear outand that interfere with high speed operations. Rate delivery, staplelength and amount of tension may be varied and controlled. It is indeedsurprising that the delivery rates can be maintained sufiicientlyconstant and uniform to obtain the desired denier uniformity and in thecase of staple to obtain substantially uniform length of the cut fiber.

In these respects, the device of this invention has been usedsuccessfully to out such yarns as melt spun polyamide yarns or suchother yarns as cellulose acetate or those from vinyl chloride/vinylacetate interpolymers. Besides being useful as a staple cutter inconnection with a spinning unit, it can be used to unwind continuousfilament yarn from a suitable package and cut it to staple on the run.Speeds up to 3000 Y. P. M. are reached. Staple length can be varied atwill by proper choice of the number of knives and through-put speed.

Any departure from the procedure described herein which conforms to theprinciples of the invention is intended to be included within the scopeof the claims below.

We claim:

1. Apparatus for handling a traveling funicular structure with a fluidunder pressure which comprises two plates situated close to each other,one of which is a blower plate having a plurality of orifices throughwhich said fiuid is emitted; and an inlet for said structure extendingthrough said blower plate.

2. Apparatus for handling a traveling funicular structure with a fluidunder pressure which comprises an upper blower plate and a lower blowerplate situated close to each other the said upper plate having aplurality of orifices to direct fluid downwardly and tangentiallyforward and the said lower plate having a plurality of orifices todirect fiuid upwardly and tangentially forward; and an inlet for saidstructure extending through one of said blower plates.

' 3. Apparatus for handling a traveling funicular structure with a fiuidunder pressure which comprises an upper blower plate and a lower blowerplate situated close to each other, each plate containing a jet andfluid inlet to said jet; and an inlet for said structure extendingthrough one of said blower plates.

4. Apparatus in accordance with claim 3 in in which said jet in each ofsaid plates comprises a plurality of holes.

5. Apparatus in accordance with claim 3 in which said jet in each ofsaid plates comprises a plurality of slots.

6. Apparatus for handling a traveling funicular structure with a fluidunder pressure which comprises an upper plenum chamber and a lowerplenum chamber, each having a blower plate and mounted so that saidplates are directly over each other separated by a small space eachplate having a plurality of orifices through which said fluid isemitted; and an inlet for said structure extending through one of saidblower plates.

7. Apparatus in accordance with claim 6 in which said plates aresubstantially circular.

8. Apparatus in accordance with claim 6 in which said holes are arrangedto give a spiral effect.

ROBERT MICHAEL HOFFMAN. FRANK KERR. SIGNAIGO.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,100,588 Claus Nov. 30, 19372,173,789 Nikles et al. Sept. 19, 1939 2,258,661 Pool Oct. 14, 19412,300,791 Lodge Nov. 3, 1942 2,302,790 Modigliani Nov. 24, 19422,340,985 Pool Feb. 8, 1944 2,426,757 Wicker Sept. 2, 1947 2,447,982Koster Aug. 24, 1948

